A New Model of Protein Adsorption Kinetics Derived from Simultaneous Measurement of Mass Loading and Changes in Surface Energy
Bibliographic record
Abstract
We describe a novel technology based on changes in the resonant frequency of an acoustically actuated surface and use it to measure temporal changes in the surface energy gamma (N m(-1)) of an elastomeric polymer membrane due to the adsorption of macromolecules from aqueous solution. The resonant elastomeric surface-tension (REST) sensor permits simultaneous determination of mass loading kinetics and gamma(t) for a given adsorption process, thereby providing a multivariable data set from which to build and test models of the kinetics of adsorption at solid-liquid interfaces. The technique is used to measure gamma(t) during the adsorption of either sodium dodecyl sulfate (SDS) or hen egg-white lysozyme (HEWL) onto an acrylic polymer membrane. The adsorption of SDS is reversible and is characterized by a decrease in gamma over a time period that coincides with that required for the mass loading of the membrane. For the adsorption of HEWL labeled with Alexa Fluor 532 dye, gamma continues to change long after the surface concentration of labeled HEWL, measured by using the elastomeric polymer membrane as an optical waveguide, reaches steady state. Gradual but significant changes in gamma(t) are observed as long as the concentration of protein in the bulk solution, c(b), remains nonzero. HEWL remains adsorbed to the membrane when c(b) = 0, but changes in gamma(t) are not observed under this condition, indicating that the interaction of bound protein molecules with those free in solution contribute to the prolonged change in the surface energy. This observation has been used to define a new model for the kinetics of globular protein adsorption to a solid-liquid interface that includes a mechanism by which the molecules in the bulk can facilitate the desorption of a sorbate molecule or change the energetic states of adsorbed molecules and, thus, the overall surface energy. The model is shown to capture the unique features of protein adsorption kinetics, including the relatively fast mass loading, the much more gradual change in surface energy that does not cease until the protein is removed from the bulk, the rapid desorption of an incubation-time-dependent fraction of bound protein when the protein is removed from the bulk, and the fixing of the residual surface concentration and surface energy at constant values once the removal of reversibly bound protein and free protein is complete.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".